Two glove-box chambers have been assembled and tested for the purpose of carrying out long-term effects of bypoxia during the perinatal period. Seven dams with litters can be maintained continually in each chamber at fixed oxygen concentrations. Humidity, temperature, CO2 and ammonia are controlled within tolerable limits. Hypoxic environments of 12% and 15% O2 during the perinatal period exert acute and subacute effects on growth characteristics of pups at 7 and 21 days of age. However no difference between hypoxia and controls with respect to steady monoamine concentrations or hippocampal histology were detected. More severe O2 deprivations coupled with more sensitive testing methods may reveal persistent effects of hypoxia on brain maturation.